| From: | "MauMau" <maumau307(at)gmail(dot)com> |
|---|---|
| To: | "Alvaro Herrera" <alvherre(at)2ndquadrant(dot)com>, "Tomas Vondra" <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Cc: | "Bruce Momjian" <bruce(at)momjian(dot)us>, <andres(at)anarazel(dot)de>, "Robert Haas" <robertmhaas(at)gmail(dot)com>, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Kyotaro HORIGUCHI" <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, "Ideriha, Takeshi" <ideriha(dot)takeshi(at)jp(dot)fujitsu(dot)com>, <pgsql-hackers(at)lists(dot)postgresql(dot)org>, "Tsunakawa, Takayuki" <tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com>, <michael(dot)paquier(at)gmail(dot)com>, <david(at)pgmasters(dot)net>, <craig(at)2ndquadrant(dot)com> |
| Subject: | Re: Protect syscache from bloating with negative cache entries |
| Date: | 2019-02-08 13:46:43 |
| Message-ID: | 7BB6D08FB81C4690BC01741E6B7B1692@tunaPC |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
From: Alvaro Herrera
> I think seqscanning the hash table is going to be too slow;
Ideriha-san
> idea of having a dlist with the entries in LRU order (where each
entry
> is moved to head of list when it is touched) seemed good: it allows
you
> to evict older ones when the time comes, without having to scan the
rest
> of the entries. Having a dlist means two more pointers on each
cache
> entry AFAIR, so it's not a huge amount of memory.
Absolutely. We should try to avoid unpredictable long response time
caused by an occasional unlucky batch processing. That makes the
troubleshooting when the user asks why they experience unsteady
response time.
Regards
MauMau
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2019-02-08 14:25:07 | Re: ON SELECT rule on a table without columns |
| Previous Message | Raúl Marín | 2019-02-08 13:30:51 | Re: [PATCH] pgbench tap tests fail if the path contains a perl special character |